Uniform pressure casing cutter



2 Sheets-Sheet l June 13, 1933. w. E. KING UNIFORM PRESSURE CASING CUTTER Filed March 30, 1928 June 13, 1933. w E KING 1,913,636

UNIFORM PRESSURE CAsING CUTTER Filed March 50, 1928 2 Sheets-Sheet 2 i: uw N 3g WM/@1. INVENTOR.

ATTORNEYS.

Patented June 13, 1933 UNITED s'livrlzs 'PATENr caricia:

- WALTER norme, or HOUs'roN, Texas, AssIGNon 'ro Janes s. ABERCROMBIE, or

' HOUSTON, Texas UNIEOBE rnnssunn casrne CUTTER Application Iarch 30,

My invention relates to cutting devices for use in deepwells in cutting-casing or other similar pipe from the well, and pertains more particularlyito inside casing cutters designed to be introduced inside of the pipe to be cut androtated to sever the pipe at th'edesired point.

In cutters of this kind now in common use where the force of the yflushing liuid isl employed Ito advancthe cutters during the cutting operation, diiiiculty, is experienced due to the fluctuations of pressure in the iushing fluid. The pumpsemployed in forc- L ing the liquid' into the drill stem are usually l5 large and'heavy umps of the reciprocating -t lpe which sen the fluid in pulsations t rough the stem. Furthermore, lit is diiicult to secure an even operation in these pumps to secure uniform pulsations.- The a0 result is that the cutters are' advanced into contact with the pi in such manner as to exert a shock upon t e cutters due to the uneven ypressure exerted upon the device, and the cutters, therefore, operate unevenly and are liable to breakage. This diliiculty is hard toovercome and is one which causes an excess breakage of cutters and a generally unsatisfactory operationoithe device. A further objection to the tools of this 80 type is that the pumpsfe'mployedsvery often v develop an excess of pressure. This condition tendsto press the cutters intothepi that is being cut, with such force that t e l vstrainy causes them to break.- .All tools in' the prior art have had rigidconnections between thepistonnnd cutter holders, and any movement of the piston would cause a movement of the cutters.

It is an object Of my invention to provide 40 means in the operation. of a cutter of this kind where the cutters `are advanced indirectly through the pressire'of the iluid, said device being so constructed as to-exert a steady and, uniform ating mandrel so that'the cutters/.may be tion, l

pressure upon the1 operisaafseriai 1ro. `2ss.os1.

sure and the cutters advanced entirely throughthe pressure of the spring. Any exft cess pressure created bythe pumps will lnot be transmitted to the cutters in myl tool because I provide a stop for'the piston, and,4 therefore, any amount of pressure above that required to force the piston to the stop is ineffective, and, as stated above, leaves the` spring the sole agency for feeding the cut- Referring to the drawings herewith, wherein'two separate embodiments of the invention are disclosed, ,f

Fig. 1 is a central longitudinal section 65 through a cutting device embodying my in vention, said device being shown as extended 'withina pipetobecut.

ig. 2 is a similar view showing the cutters in advanced position with the pipe severed. 7 ,0

' ig. 3 is a similar view to that shown in Fig. 1, but illustrating a different embodiment. of the invention.I

Fig. 4 isa similarl view to that shown in Figi but with the cutters in advanced posi# 75 The pipe 'cutter which is disclosed in my inventionfis similarin general construction to i other'snow on the market, butA has attached thereto my novel means of operating said v cutters. 'The cutter employs a head 1 which has a central recess or chamber 2 Atherein fori the operation of the holder 3 for the cutters. The head 1 is provided l.with a threaded socket 4 atits upper 'end to receive a nipple 5. At 85 its lower end it is provided with 'a threaded shank 6 'adapted to beengaged. within the upper end 7 of a milling tool or guide shoe 8. The head 1 is rovided with a. plurality ofopenings 9 'whidli are inclined downwardly 90 and the lower walls 10 of said openings form a deflecting cam surface' upon which the cutters 11 may ride. The chamber 2 within the head 1 isvdecreased in diameter below the shoulders 10 and forms a guide passage '12 for a lower projection 13 upon the holder. At the lower end of the passage 12 is a transverse wall 14 which is perforated at 15 to allow the passage of fluid. Centrally of this wall is secured a threaded valve stem 16 which projects upwardly into the passage 12 and has thereon a stationary valve head 17 tapering upwardly. The lower end of said valve stem is slotted at 18 to receive a screw 'driver or similar tool whereby the valve 17 may be adjusted vertically in an obvious manner. The lower end of the milling tool 8 .is provided with a central passage 19 through which a tool may be inserted for adjusting said valve.

The cutter holder 3 has its lower end shaped to fit within the chamber 2 and the passage 12, as has been mentioned, and is adapted to have a' limited vertical sliding movement therein. The cutters 11 are pivoted to the lower end of the head at 20, and it will be obvious from the drawings that when the head is moved downwardly lthe cutters sliding on the shoulder 1() will be deflected out a ainst the casing. This type of cutter is not elieved to be new in the art.

The upper end of the holder 3 is cylindrical and fits within the central passage 21 through the nipple 5. It is hollow and has a cylinder 22 therein to receive a head 23 upon a mandrel 24 slidable therein. The upper end of the cylinder 22 is closed about the mandrel by a cap 25 screwed upon the upper end of said cylinder.

The mandrel 24 is tubular and the head 23 comprises a radial flange between which and a nut 26 is clamped a packing cup 27 which vmakes a sliding fluid tight fit with the cylinder. Said mandrel extends upwardly above the nipple within a barrel 28 andhas screwed upon its upper end a bearing nut 29 for a coiled spring 30; and a piston head 31, the nut being spaced downward from the piston head. Below the head is a lock nut and bearing member 32.

The head has a packing ring 3.3 held in position by a nut 34. The interior of the barrel 28 forms a cylinder in which the piston head fits slidably. Between the nut 32 and the shoulder 35 formed at the upper end of .the nipple 5 is a spring 36 which tends to hold the` mandrel and piston` in raised position.

I' may employ a. strainer for the fluid pass- Ving through the device and I have shown a bull plug 37 screwed into the upper end of the piston, said plug having straining slots 38 formed therein to allow the fluid to pass into the passage 39 through the mandrel.

In use, the device is connected to a pipe or drill vstem 40 and lowered into thecasing to the point where the cut is to be made. Water is pumped downwardly through the device while it is being lowered to clear the well ahead. If obstructions areencountered, the milling tool 8 may be rotated to clear the passage. When the proper lever hasbeen reached, the drill stem will be firmly s upported at the surface for rotation. The pump pressure will be then increased to exert sufficient force to move the piston and manzrel downwardly against the pressure of the spring 36.

This downward movement will move the head 23 downwardly in the cylinder 22 and the spring 36 will be compressed to the position shown in Fig. 2. This is the downward limit of movement of the mandrel. The downward movement vof the mandrel will compress the spring 30 so as to exert a pressure'upon the holder 3 and move it downing. The tool will then be rotated and the cutters will mill a channel in the casing which will eventually cut through the casing wall and sever the upper section.

yAs the cuttingis in progress the fluid pressure will be maintained but inequalities therein will not be noticeable upon the cutters as the said cutters. are advanced solely by the spring 30, and this pressure will be a constant one. lVhen the holder has been moved down far enough to advance the cutters entirely through the casing, as shown in Fig. 2, the lower end of the guide member 13 will seat upon the lvalve 17, sealing the passage of fluid through the device. This will slow up or stop thepumps to indicate to the operator that thel cut has been finished. It will be noted that the valve may be set at the desired height toshut ofi' the circulation at the point where the casing will be severed and this point may be varied to suit the'particular casing being cut. The pump pressure may be next released and the spring 36 will raise the mandrel to withdraw the cutters. j

In the smaller sizes of casing cutters, there may: be insufficient space to allow for a cylinder 22 in the holder and I may, therefore, alter the construction somewhat to meet these conditions and still get the same result. In Figs. 3 and 4 an embodiment of the invention is shown which is adaptable for the smaller sizes.

In this embodiment the mandrel 24 has a head 41 that extends through the holder andis screwed within the guide 13. It hasashoulder 42 above the holder to form a seat for the upon the mandrel 24. 'It has a head 31 upon which is a supporting wall 44 threaded beth externallyand internally. The outersurface furnishes a seat for' packing cups 45 and spacing rings 46; and the inner face receives packing rings47 and spacers 48 making a fluid tight fit with the mandrel. A ring nut 48 holds the outer rings in place and an interior nut 49 serves to lock the interior rings in position. Above the piston are stop nuts 50 limiting the upward travel of the piston on the mandrel and adapted to be adj usted thereon in an obvious manner.

' In this embodiment, the strainer 37 is formed upon a disc 51 adapted to screw into the upper end of the barrel and is therefore stationary.

In the operation of this embodiment, the pressure of the iiushing fluid exerted upon the piston 31 will force it downward into contact with the shoulder 35 at the upper end 'of the nipple 5', thus compressing the spring 36, and'also the will exert a uniform pressure upon the holder to advance thecutters, as previously explained. When the cut has been made, the release of the pump pressure will cause both springs to expand to ing the cutters.

The advantages ofl this type of cutter advancing means is that the cutters will be acted upon by a steady and constant pressure uring the cutting operation and no change in the level of the cutters will occur during the cutting of the casing. f This will assure a smooth and even so that they will not be damaged and will tend to avoid breaking ofthe cutters in use. Greater accuracy and better quality of work is assured.

Having thus described the invention, what I claim is:

e 1. A pipe cutter including a liead, a holder slidable in said head, cutters on said holder adapted to be advanced by the downward 3 movement thereof, 45

able thereon,means to hold adapted to be compressed by the downward movement of said piston, to exert a Steady pressure upon said holder to advance said cutters. 4 l 2. lA pipe cutter including a head, a holder slidable insaid head, cutters on said holder adapted to be advanced by the downward movement thereof, a mandrel, a piston slidable Ithereon, a spring to hold said piston and mandrel resiliently upward, and a spring adapted tobe compressed by the downward movement of said iston with respect to said mandrel, said ho 69 the pressure of said last spring to advance said cutters. 4 y

8. In a device of the character described, a head, a holder movable therein, cutters on said holder adapted to be moved radially by 65 the vertical movement of said holder, amanspring 30. The spring 30 return the piston to its upper posi-4 tion, moving up the mandrel and withdraw-` pressure upon these cutters a mandrel, a piston slidsaid piston Aand mandrel resiliently upward, and a spring WALTER E. KING.

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der being responsive tov 

